JP2008025453A - Injector drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injector drive device capable of inhibiting fluctuation of valve open response time of an injector of an internal combustion engine of a low cost structure. <P>SOLUTION: A wave form generator 11 synchronizes with injection valve signal for making an injector INJ inject, and creates reference current signal which makes injector current wave form when low voltage is applied to the injector INJ roughly equivalent to current rise tendency. A current detection resistance R3 and an operational amplifier 15 detect current flowing to the injector INJ as detected current signal. A comparator 12 compares reference current signal and detected current signal and controls electricity supply to the injector INJ. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

 The present invention relates to an injector drive device, and more particularly to an injector drive device that drives an injector of an internal combustion engine to which power is directly supplied from a battery.

  2. Description of the Related Art As a fuel injection device for an internal combustion engine, for example, an internal combustion engine mounted on a vehicle such as an automobile, an electromagnetic fuel injection device (hereinafter referred to as “injector”) is known. Such an injector includes a nozzle having a fuel injection hole, a plunger that is reciprocally inserted into the nozzle and has a valve (valve element) formed on the tip side thereof, and a return spring that gives the plunger an elastic force in the valve closing direction. And a coil that receives electromagnetic power from the battery and applies electromagnetic force in the valve opening direction to the plunger. When the coil is energized, the plunger is sucked, the valve is separated from the valve seat of the fuel injection hole, and the fuel is The fuel is injected from the fuel injection hole. On the other hand, when energization to the coil is stopped, the magnetic attractive force by the coil is attenuated, and the valve is closed by the elastic force of the return spring.

  In recent years, in order to improve combustion efficiency, an attempt has been made to directly inject fuel into a cylinder by arranging an injector (fuel injection device) in a cylinder of a gasoline engine. According to this direct injection of fuel into the cylinder, all gasoline fuel supplied from the injector is supplied into the cylinder, so that it is possible to achieve combustion closer to the theoretical value, improving fuel consumption, and exhaust gas. Reduction of NOx, HC, etc. can be realized.

  However, in the case of direct injection, the space in which gasoline fuel is injected is a space composed of a cylinder block, a piston, and a cylinder head. Considering injection during the compression stroke, it is compared with the case where it is injected into the intake manifold. Therefore, the injection must be performed under a very high pressure. Further, there is no space and time allowance for sufficient diffusion of fuel after fuel injection. Therefore, under these conditions, in order to obtain the same combustion conditions as before, it is necessary to increase the fuel pressure of the gasoline fuel supplied to the injector and sufficiently diffuse the fuel from the moment when it is injected into the cylinder. There is. For this purpose, it is necessary to drive the injector at high speed against high fuel pressure and to accurately control the fuel injection time. The drive circuit also applies a high voltage to the injector (specifically, the injector solenoid) in a short time. Thus, it is necessary to open and close the needle valve of the injector at a high speed.

  For example, in Patent Document 1, in an injector drive circuit of an in-cylinder direct injection engine, a high fuel pressure is applied to the injector and a large electromagnetic attraction force is required for the coil of the injector. A technique is disclosed in which a voltage obtained by boosting a battery voltage (+ B) to about 50 to 200 V by a booster is applied to operate an injector, and then the battery voltage (+ B) is switched to a holding current.

  However, the technique disclosed in Patent Document 1 has advantages such as a short valve opening response time (T0) of the injector and that it is not affected by fluctuations in the battery voltage (+ B). There is a problem that a booster is required and noise countermeasures are required because a high voltage is used, resulting in a high cost of the device.

  In order to solve the above problem, in Patent Document 2, the injector is driven by the battery voltage (+ B), the threshold value for switching to the constant current control is changed according to the battery voltage (+ B), and this threshold value is changed to the battery voltage (+ B). A technology for preventing excessive current when the battery voltage is low is disclosed by setting the value smaller as the battery voltage is lower.

  However, when the injector drive current is controlled by the battery voltage (+ B) without using the booster as in the cited document 2, the applied voltage applied to the injector becomes a low voltage, and the change in the battery voltage and between each cylinder There is a problem that it is difficult to suppress (fix) the fluctuation time of the valve opening response time T0 of the injector due to the inherent variation.

  With reference to FIGS. 10-12, the fluctuation | variation of the valve opening response time T0 of an injector is demonstrated. FIG. 10 is a diagram for explaining the applied voltage applied to the injector and the valve opening response time T0 of the injector. In the figure, the horizontal axis indicates the applied voltage of the injector INJ, the vertical axis indicates the valve opening response time T0 of the injector INJ, and when A is driven by the battery voltage (+ B), B uses the booster. It shows the case of driving.

  When driven by using a booster, as described above, even if the applied voltage fluctuates, the fluctuation range ΔT0 of the valve opening response time T0 of the injector INJ is small, and there is no particular problem. On the other hand, in the case of driving only with the battery voltage (+ B), when the applied voltage of the injector INJ varies, the fluctuation range ΔT0 of the valve opening response time T0 of the injector INJ increases. The applied voltage applied to the injector INJ varies depending on the variation of the battery voltage (+ B) and the variation of the coil resistance (including the resistance of the harness) due to the ambient temperature, change with time, and the like.

  FIG. 11 is a diagram for explaining the valve opening response time T0 when the injector is controlled at a constant voltage, and FIG. 12 is a diagram for explaining the valve opening response time T0 when the injector is controlled at a constant current. FIG. As shown in FIGS. 11 and 12, the current rising tendency of the current flowing through the injector INJ is different between when the applied voltage is high and when it is low. The valve opening response time T0 of the injector INJ changes greatly due to the rising tendency of the current flowing through the injector INJ. Thus, the conventional constant voltage control method and constant current control method that do not use a booster circuit have a problem that fluctuations in the valve opening response time T0 cannot be suppressed.

JP 11-351039 A JP 2001-41085 A

  The present invention has been made in view of the above, and an object of the present invention is to provide an injector driving device capable of suppressing fluctuations in the valve opening response time of an injector of an internal combustion engine with a low-cost configuration.

  In order to solve the above-described problems and achieve the object, the present invention provides an injection valve signal for injecting an injector in an injector driving apparatus for an internal combustion engine that drives an injector to which electric power is supplied directly from a battery. Reference current signal generating means for generating a reference current signal that is synchronized with the injector current waveform when the low voltage is applied to the injector and the current rising tendency is substantially equivalent, and a current that flows through the injector is detected current signal Current detection means for detecting the current and the reference current signal are compared with the detected current signal, and current supply control means for controlling current supply to the injector is provided.

  Further, according to a preferred aspect of the present invention, it is desirable that the reference current signal has a waveform shape that has an increasing tendency from the rise of the direct injection valve signal and falls at the fall of the direct injection valve signal.

  According to a preferred aspect of the present invention, it is desirable that the reference current signal changes stepwise to a second current value set lower than the first current value when the first current value is exceeded.

  Further, according to a preferred aspect of the present invention, it is desirable that the reference current signal is substantially equivalent to an injector current waveform when the battery voltage is low and the injector is energized under predetermined operating conditions.

  According to a preferred aspect of the present invention, it is desirable that the reference current signal has a waveform that approximates the injector current waveform with a triangular wave.

  According to a preferred aspect of the present invention, it is desirable that the reference current signal generating means is common to the injectors of the respective cylinders.

  According to a preferred aspect of the present invention, it is desirable that the energization control means controls energization of the injector with a constant voltage when the battery voltage is equal to or lower than a threshold value.

  According to the present invention, in an injector driving device for an internal combustion engine that drives an injector to which power is directly supplied from a battery, the reference current signal generating means is synchronized with an injection valve signal for injecting the injector, and A reference current signal is generated in which the current rising tendency is substantially equivalent to the injector current waveform when a low voltage is applied to the injector, and the current detection means detects the current flowing through the injector as a detection current signal, and controls energization Since the means compares the reference current signal with the detected current signal and controls energization of the injector, the valve opening response time of the injector is controlled to be substantially constant even when the applied voltage of the injector fluctuates. An internal combustion engine that can suppress fluctuations in the valve opening response time of the injector with a low-cost configuration that does not use a booster circuit It is possible to provide an injector driving apparatus Seki.

  Exemplary embodiments of an injector driving device according to the present invention will be explained below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or that are substantially the same.

(Embodiment 1)
FIG. 1 shows an injector driving device that drives (excites) a coil L1 of an injector INJ of an internal combustion engine (engine). In the figure, the injector INJ is shown as an equivalent circuit of a coil L1 and a resistor R1. In the figure, a drive device for driving one injector coil L1 corresponding to one cylinder among the coils of the injector provided for each cylinder of the engine is shown as an example.

  In the figure, an injector driving device 1 controls energization of a coil L1 in accordance with an injector signal input from an ECU 2. The ECU (engine controller unit) 2 outputs an INJ signal (injection valve signal) determined according to the engine operating state, such as the throttle opening, to the injector driving device 1. The battery B is connected in series to the injector INJ, and supplies the battery voltage (+ B) to the injector INJ. The injector INJ is supplied with the battery voltage (+ B) from the battery B, and the injector driving device 1 controls the conduction of the coil L1.

  The injector driving device 1 includes a waveform generator 11, a comparator 12, an AND circuit 13, a protection resistor R 2, a power transistor 14, a current detection resistor R 3, and an operational amplifier (differential amplifier) 15. In the above configuration, the waveform generator 11 functions as reference current signal generation means, the comparator 12, the AND circuit 13, and the power transistor 14 function as energization control means, and the current detection resistor R3 and the operational amplifier (differential amplifier) 15 function as current detection means. To do.

  The waveform generator 11 generates a reference current signal that is synchronized with the INJ signal input from the ECU 2 and that has a current increase tendency substantially equivalent to the injector current waveform when a low voltage is applied to the injector INJ. 12 and the AND circuit 13. Details of the reference current signal will be described later.

  The comparator 12 compares the reference current signal input from the waveform generator 11 with the detection current signal input from the operational amplifier 15. When the detection current signal ≧ the reference current signal, the comparator 12 is “L”, and the detection current signal < A comparison signal that is “H” in the case of the reference current signal is output to the AND circuit 13. The AND circuit 13 outputs an AND output of the INJ signal input from the ECU 2 and the comparison signal input from the comparator 12 as an energization control signal to the gate of the power transistor 14 via the protective resistor R2.

  The power transistor 14 has a gate connected to the AND circuit 13 via the protective resistor R2, an input side connected to one end of the coil L1 of the injector INJ, and an output side connected to the current detection resistor R3. The power transistor 14 conducts the coil L1 of the injector INJ according to the energization control signal input to the gate. In addition, it is good also as a structure which prevents a backflow by carrying out the antiparallel connection of the diode to the both ends of the power transistor 14. FIG.

  The current detection resistor R3 is a resistor for detecting a current (injector current) flowing through the coil L1 of the injector INJ. One end side of the current detection resistor R3 is connected to the output side of the power transistor 14, and the other end side is grounded. The voltage between both ends of the current detection resistor R3 has a voltage value corresponding to the injector current.

  The operational amplifier 15 is connected in parallel to the current detection resistor R3, and differentially amplifies the voltage between both ends of the current detection resistor R3 and outputs it to the comparator 12 as a detection current signal.

  Next, the reference current signal generated by the waveform generator 11 will be described in detail. FIG. 2 shows the injector current waveform and the response of the injector INJ when the voltage applied to the injector INJ is V1, V2, and V3 (where V1 <V2 <V3), and the injector INJ is energized. The current rising tendency of the injector current differs depending on the voltage applied to the injector INJ, and the current rising tendency is smaller as the applied voltage is lower. The valve opening response time T0 of the injector INJ depends on the current rising tendency of the injector current. The lower the applied voltage, the longer the valve opening response time T0 of the injector INJ.

  In the present embodiment, the applied voltage of the injector INJ is such that the valve opening response time T0 of the injector INJ is substantially constant regardless of fluctuations in the applied voltage of the injector INJ (battery voltage fluctuation, coil resistance fluctuation, etc.). A common reference current signal is generated so that the current rising tendency is substantially equivalent to the injector current waveform when V is low voltage (for example, V1), and control is performed so that the injector current waveform follows this common reference current signal. is doing. As described above, in the present embodiment, when the applied voltage of the injector INJ is a low voltage, that is, the side where the valve opening response time T0 of the injector INJ is long (the side where the valve opening response is bad) is used as a reference. Even when a current signal is generated and the applied voltage becomes a high voltage, the valve opening response time T0 is controlled to be the same as when the voltage is low.

  The operation and effect of the injector drive circuit 1 configured as shown in FIG. 1 will be described with reference to FIGS. FIG. 3 is a diagram for explaining the drive system of the present invention, and shows the response of the injector INJ when the applied voltage of the injector is low and high. In this figure, (a) is the INJ signal, (b) is the operation of the injector INJ when the applied voltage is high, (c) is the reference current signal when the applied voltage is high, and (d) is the high applied voltage. (E) is the operation of the injector INJ when the applied voltage is low, (f) is the reference current signal when the applied voltage is low, and (g) is the injector when the applied voltage is low The current waveform is shown. FIG. 4 is a diagram for explaining the followability of the injector current to the reference current signal. In the figure, the horizontal axis indicates time t and the vertical axis indicates voltage.

  1, the waveform generator 11 generates a reference current signal that is synchronized with the INJ signal (see FIG. 3A) input from the ECU 2 and outputs the reference current signal to the comparator 12 and the AND circuit 13. The Here, the reference current signal has a waveform in which the current rising tendency is substantially equivalent to the injector current waveform when the applied voltage of the injector INJ is low, and from the rise of the INJ signal (at the start of energization). It shows an increasing tendency, and has a waveform that falls (returns to 0A) at the fall of the INJ signal (at the end of energization) (see FIGS. 3C and 3F).

  In the comparator 12, a reference current signal is input from the waveform generator 11, and a detection current signal corresponding to the current flowing from the operational amplifier 15 to the coil L1 of the injector INJ is fed back. The comparator 12 compares the reference current signal and the detected current signal, and the comparison signal that is “L” when the detected current signal ≧ reference current signal and “H” when the detected current signal <reference current signal is AND. It is output to the circuit 13. In the AND circuit 13, an AND output of the INJ signal input from the ECU 2 and the comparison signal input from the comparator 12 is output to the gate of the power transistor 14 via the protective resistor R2 as an energization control signal. Here, the reason why the energization control signal is an AND output of the comparison signal and the INJ signal is to prevent a current from flowing through the coil L1 of the injector INJ while the INJ signal is OFF. The power transistor 14 is turned ON / OFF according to the energization control signal input from the AND circuit 13 via the protective resistor R2, and the coil L1 of the injector INJ is turned on / off. Thus, the waveform of the current flowing through the coil L1 of the injector INJ (injector current waveform) is controlled so as to follow the waveform of the reference current signal (FIGS. 3C, 3D, 3F, and 3G). ), See FIG.

  Thus, even when the applied voltage is high, even when the applied voltage is high, the current tends to increase (see FIGS. 3D and 3G). By making the suction force of the injector INJ constant, The injector response time T0 can be made constant (see FIGS. 3B and 3E), and fluctuations in the injector response time T0 due to applied voltage fluctuations (battery voltage fluctuations, coil resistance fluctuations, etc.) can be prevented. It becomes.

FIG. 5 shows the measurement results of the valve opening response time T0 of the injector INJ between the driving method according to the present invention and the conventional constant voltage control method. In the figure, the horizontal axis represents the voltage applied to the injector INJ, and the vertical axis represents the valve opening response time T0 of the injector INJ. As shown in FIG. 5, in the drive system according to the present invention, the fluctuation range ΔT0 of the valve opening response time T0 of the injector INJ with respect to the fluctuation of the applied voltage is much smaller than that in the conventional constant voltage control system. It has been confirmed that the drive system according to the present invention is effective in suppressing fluctuations in the valve opening response time T0 of the injector INJ.

  Next, Examples 1 to 3 of the reference current signal will be described. The reference current signal has a shape in which the current rising tendency is substantially equivalent to the injector current waveform when the applied voltage of the injector INJ becomes a low voltage. You may make it into a shape.

[Example 1]
The reference current signal may be approximated by a triangular wave. As shown in FIG. 2, each injector current waveform when the injector INJ is energized generally has a triangular wave (straight line) shape. Therefore, a signal that approximates the injector current waveform with a triangular wave is used as a reference current signal. Can be used. Since the triangular wave can be generated with a simple configuration such as an RC circuit, the waveform generator 11 can be configured simply and at low cost, and the injector driving device can be configured at low cost. Note that the waveform to be approximated is not limited to a triangular wave, and may be approximated by, for example, a trapezoidal wave or a curved wave, and an approximation that can be evaluated as being approximately equivalent to an injector current waveform when the applied voltage is low. Any waveform signal may be used as long as it has a waveform.

[Example 2]
FIG. 6 is a diagram for explaining the reference current signal according to the second embodiment. In this figure, (a) is the INJ signal, (b) is the operation of the injector INJ when the applied voltage is high, (c) is the reference current signal when the applied voltage is high, and (d) is the high applied voltage. (E) is the operation of the injector INJ when the applied voltage is low, (f) is the reference current signal when the applied voltage is low, and (g) is the injector when the applied voltage is low A current waveform is shown, and Tc shows a valve closing response time.

  In the figure, the reference current signal is set lower than the constant value (first current value) when the continuously increasing current value exceeds a certain value (first current value) required for the injector INJ operation. The holding current value (second current value) may be changed to a step shape. In this case, similar to the first embodiment, it can be approximated by a triangular wave until a constant value is reached.

  Since the current value becomes excessive after the injector INJ is operated, this excessive current causes energy consumption deterioration and deterioration of the valve closing response time Tc of the injector INJ. Therefore, after the injector INJ is operated, the minimum necessary holding for maintaining the valve opening is maintained. Switch to current. Thereby, it is possible to prevent deterioration of energy consumption and the valve closing response time Tc of the injector INJ from becoming longer.

[Example 3]
The reference current signal may be a waveform substantially equivalent to the injector current waveform when the injector INJ is energized under a specific condition (the battery voltage (+ B) is a low voltage and a predetermined operating condition). Thus, the operating state can be matched by making the waveform of the reference current signal equivalent to the actual waveform. In this case, a specific condition is that the injector current has the slowest rate of increase in the injector INJ and the engine within the operating condition (during normal engine rotation) in which fluctuation of the valve opening response time T0 of the injector INJ becomes a problem. It can be.

  The battery voltage (+ B) changes depending on the engine speed and the electric load, and the coil resistance and harness resistance of the injector INJ also change depending on the ambient temperature. Using the operating conditions (engine speed, ambient temperature, etc.) and battery voltage (+ B) as parameters, the electromagnetic attraction force of the injector INJ in advance so that the injector INJ can be operated under the condition that the injector current has the slowest rate of current rise. Set. By controlling the current rising tendency of the injector current under this condition, the valve opening response time Tc can be made constant under the slowest condition regardless of the variation of the battery voltage (+ B) and the operating condition. It should be noted that such control is not necessary for regions where the injection time is long and the engine is running at a low speed and fluctuations in the valve opening response time of the injector INJ are not a problem, such as cold start.

  As described above, according to the present embodiment, in the injector driving device for an internal combustion engine that drives the injector INJ that is directly supplied with power from the battery B without using the booster circuit, the waveform generator 11 includes: A reference current signal is generated in synchronism with the injection valve signal for injecting the injector INJ and the current increase tendency is substantially equivalent to the injector current waveform when a low voltage is applied to the injector INJ, and the current detection resistor R3 The operational amplifier 15 detects the current flowing through the injector INJ as a detection current signal, and the comparator 12 compares the reference current signal and the detection current signal to control the energization of the injector INJ. The injector response time T0 can be kept constant even when the battery voltage fluctuates (battery voltage fluctuation, coil resistance fluctuation, etc.) It is possible to prevent fluctuations in the injector response time T0 due to variations in applied voltage (battery voltage (+ B) of the variation or fluctuation of the coil resistance, etc.). Thereby, air-fuel ratio control, combustion stability can be improved, and emissions can be reduced.

  In addition, in this embodiment, correction for the amount of change in the battery voltage (+ B) is not necessary, so control is simple, and feedback control is performed, so control can be performed more accurately than map correction. It becomes.

  In the present embodiment, the injector driving device for one injector corresponding to one cylinder of the internal combustion engine (engine) has been described. However, in the injector INJ of each cylinder, the injector having the slowest valve opening response time T0. By matching the valve opening response time T0 of the injector INJ of the other cylinder with the INJ, that is, the reference current signal approximating the injector current waveform of the injector INJ of the cylinder having the slowest valve opening response time T0 is obtained. By using this injector control device, the valve opening response time T0 of the injector INJ can be made constant between the cylinders.

  Further, in the present embodiment, since the energizing current to the injector INJ is made constant, the suction force of the injector INJ is made constant, and the change in the valve opening response time T0 is prevented, so that it cannot cope with the change in the applied fuel pressure. . For this reason, the ECU 2 may correct the injection start timing and the energization time with a map or the like for the fuel pressure change.

(Embodiment 2)
FIG. 7 is a configuration diagram illustrating an injector driving device according to the second embodiment. In FIG. 7, parts having the same functions as those in FIG. The injector drive device according to Embodiment 2 has a configuration in which a common waveform generator 11 is used when the INJ signal width of the injector INJ of each cylinder is the same. This figure shows the case of four cylinders as an example. In FIG. 7, when the INJ signal widths of the injectors INJ1 to INJ4 are the same and the suction force and fuel pressure of the injectors INJ1 to INJ4 with respect to the current are the same, a common reference current signal can be used. ), It is not necessary to provide a waveform generator every time, and one waveform generator 11 can be used instead. FIG. 8A shows an example of a timing chart of the INJ signals and reference current signals of the injectors INJ1 to INJ4. For example, as shown in FIG. 8A, when the signal widths of the INJ signals of the INJ1 to INJ4 are the same and the INJ signals do not overlap, the reference current signal for each of the INJ1 to 4 is generated by one waveform generator 11. Can be generated.

  When the INJ signal overlaps with each cylinder, a single waveform generator cannot generate a reference current signal corresponding to each cylinder. Therefore, it is necessary to provide a plurality of waveform generators as long as the INJ signal does not overlap. FIG. 8-2 shows an example of a timing chart of the INJ signals and reference current signals of the injectors INJ1 to INJ4. For example, in the case of INJ signals INJ1 to INJ4 as shown in FIG. 8-2, two waveform generators are required for the injectors INJ1 and 3 and for the injectors INJ2 and 4.

  According to the second embodiment, since the common waveform generator 11 is used for the injectors of the respective cylinders, the injector driving device can be configured at a low cost.

(Embodiment 3)
FIG. 9 is a diagram illustrating a configuration of the injector driving device according to the third embodiment. In the injector driving device according to the third embodiment, in the first embodiment, when the battery voltage (+ B) is equal to or lower than the threshold value, it is not an energization control signal based on the comparison between the reference current signal and the detected current signal in the comparator 12. The injector INJ is controlled using a constant voltage value (INJ signal) as an energization control signal. In FIG. 9, parts having the same functions as those in FIG. When the battery voltage drops significantly as in the low temperature start, the current increase speed set in the third embodiment is less than the slowest condition, so that the energization of the injector INJ is controlled with a constant voltage.

  The injector driving device according to the third embodiment compares the threshold voltage V0 (where V0 <V1) and the battery voltage (+ B), “H” when the battery voltage (+ B) ≦ the threshold voltage V0. A comparator 21 that outputs “L” when voltage (+ B)> threshold voltage, and an AND circuit 22 that outputs an AND output of the output of the comparator 21 and the INJ signal to the power transistor 14 via the protective resistor R2. And. In such a configuration, when battery voltage (+ B) ≦ threshold voltage V0, the INJ signal output from the AND circuit 22 is not the energization control signal based on the comparison between the reference current signal and the detected current signal in the comparator 12. The energization of the injector INJ is controlled by the energization control signal based on the above. On the other hand, when battery voltage (+ B)> threshold voltage V0, energization of injector INJ is controlled by an energization control signal based on the comparison between the reference current signal and the detected current signal in comparator 12. Here, when battery voltage ≦ threshold voltage V0, the injector INJ is controlled at a constant voltage until battery voltage (+ B)> threshold voltage V0, but when battery voltage (+ B) ≦ threshold voltage V0, After performing the constant voltage control for a certain time, the energization control of the injector INJ based on the comparison between the reference current signal and the detected current signal may be performed.

  According to the third embodiment, when the battery voltage (+ B) at the time of starting or the like is equal to or lower than the threshold voltage V0, it is possible to ensure safety because the energization of the injector is controlled with a constant voltage. Become.

  The injector drive device according to the present invention can be suitably used for an in-cylinder direct injection engine, but can also be used for other types of engines.

  The injector drive device according to the present invention can be used for various internal combustion engines such as cars, and is particularly useful for in-cylinder direct injection engines such as cars.

It is a figure which shows the example of a schematic structure of the injector apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the injector current waveform at the time of energizing an injector by changing the applied voltage of an injector, and the responsiveness of an injector. It is a figure which shows the responsiveness of the injector INJ when the applied voltage of an injector is a low voltage and a high voltage. It is a figure for demonstrating the followable | trackability with respect to the reference current signal of an injector current. It is a figure which shows the measurement result of the valve opening response time of the injector of the drive system by this invention, and the conventional constant voltage control system. 10 is a diagram for explaining a reference current signal according to Embodiment 2. FIG. It is a figure which shows the example of a schematic structure of the injector apparatus which concerns on Embodiment 2. FIG. It is a figure which shows an example of the timing chart of the INJ signal of each injector, and a reference current signal (the 1). It is a figure which shows an example of the timing chart of INJ signal of each injector, and a reference current signal (the 2). It is a figure which shows the structural example of the outline of the injector apparatus which concerns on Embodiment 3. FIG. It is a figure for demonstrating the applied voltage applied to an injector, and the valve-opening response time T0 of an injector. It is a figure for demonstrating the valve opening response time T0 of an injector at the time of controlling an injector with a constant current. It is a figure for demonstrating the valve opening response time T0 of an injector at the time of controlling an injector by a constant voltage.

Explanation of symbols

1 Injector drive unit 2 ECU (Engine controller unit)
11 Waveform Generator 12 Comparator 13 AND Circuit 14 Power Transistor 15 Operational Amplifier (Differential Amplifier)
21 Comparator 22 AND circuit INJ Injector B Battery R1, R2, R3 Resistance L1 Coil

Claims (7)

In an injector driving device for driving an injector of an internal combustion engine to which power is directly supplied from a battery,
A reference current signal generating means that generates a reference current signal that is synchronized with an injection valve signal for injecting the injector and that is substantially equivalent to a current rising tendency when a low voltage is applied to the injector. When,
Current detection means for detecting a current flowing through the injector as a detection current signal;
An energization control means for controlling energization of the injector by comparing the reference current signal and the detected current signal;
An injector driving device comprising:   2. The injector driving device according to claim 1, wherein the reference current signal has a waveform shape that has a tendency to increase from a rise of the direct injection valve signal and falls at a fall of the direct injection valve signal.   3. The injector according to claim 1, wherein when the reference current signal exceeds a first current value, the reference current signal changes stepwise to a second current value set lower than the first current value. 4. Drive device.   2. The injector driving device according to claim 1, wherein the reference current signal is substantially equivalent to an injector current waveform when the battery voltage is low and the injector is energized under predetermined operating conditions.   The injector driving device according to claim 1, wherein the reference current signal is a waveform obtained by approximating the injector current waveform with a triangular wave.   The injector driving device according to any one of claims 1 to 5, wherein the reference current signal generating means is made common to the injectors of the respective cylinders.   2. The injector driving device according to claim 1, wherein when the battery voltage is equal to or lower than a threshold value, the energization control unit controls energization of the injector with a constant voltage.

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